Question: $\dfrac{4}{8} - \dfrac{2}{10} = {?}$
Explanation: $ = {\dfrac{4 \times 5}{8 \times 5}} - {\dfrac{2 \times 4}{10 \times 4}} $ $ = {\dfrac{20}{40}} - {\dfrac{8}{40}} $ $ = \dfrac{{20} - {8}}{40} $ $ = \dfrac{12}{40}$